std::unordered_map<Key,T,Hash,KeyEqual,Allocator>:: ~unordered_map

From cppreference.com

~unordered_map ( ) ;
(since C++11)

A destructor . Destructs the unordered_map . The destructors of the elements are called and the used storage is deallocated. Note, that if the elements are pointers, the pointed-to objects are not destroyed.

Complexity

Linear in the size of the unordered_map .